GD&T for surafce profile

Please expand on what you are asking i.e What is the application and what are you trying to achieve. The precision with which you apply GD & T is completely dependent on the application and what you are trying to achieve.

Try ANSI Y15.4M spec. It will answer all you questions on GD & T. It can be downloaded electronically or you can order it hard copy.

On a profile, the tolerance value represents the distance between two boundaries disposed about the true profile or entirely disposed on one side of the true profile. Profile tolerances apply normal (perpindicular) to the true profile at all points along the profile. The boundaries of the tolerance zone follow the geometric shape of the true profile. The actual surface or line element must be within the specified tolerance zone and all variations from the true profile must blend.

As a designer, YOU specify what the range and tolerances are.

As a manufacturer, ask the designer if you don't understand the drawing.

If you don't know what those symbol means or how to use them, consult someone with ASME GD&T certification. Or go through the training and become one.

Google and you'll find a few companies that'll provide training and consulting.

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